Doesn't fire, at all. No visual effects, no sounds, nothing in the combat log, no changes in health, nothing. 

 

The Black Path works, for what that's worth, so there is one paladin on-kill ability working.

 

Just hit level two, so it's broken from the start.

Edited March 30, 201510 yr by Shizuka2

It actually does work, but only applies to companions.  The talent seems very under budget, though, as it only triggers when the paladin makes the killing blow, does not scale (even with might), and has a small radius of effect (about 4-5 m, which may not scale with int).